Canadian Anaesthetists' Society journal
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It has been suggested that the size of the base of the tongue is an important factor determining the degree of difficulty of direct laryngoscopy. A relatively simple grading system which involves preoperative ability to visualize the faucial pillars, soft palate and base of uvula was designed as a means of predicting the degree of difficulty in laryngeal exposure. The system was evaluated in 210 patients. The degree of difficulty in visualizing these three structures was an accurate predictor of difficulty with direct laryngoscopy (p less than 0.001).
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To determine the effect of intravenous lidocaine on the intraocular pressure (IOP) response to laryngoscopy and intubation, twenty unpremedicated children, ages one to ten years were studied. After administration of either intravenous sterile water (control) (n = 10) or preservative-free lidocaine (1.5 mg X kg-1) (n = 10), anaesthesia was induced with pancuronium (0.15 mg X kg-1), thiopentone (5 mg X kg-1), and atropine (0.02 mg X kg-1), and maintained with halothane, nitrous oxide and oxygen. The trachea was intubated one minute after administration of thiopentone. ⋯ At each measurement (except time 0), IOP was significantly greater in the control group than in the lidocaine group (p less than 0.05). Heart rate and systolic blood pressure did not increase significantly in either group after intubation. We conclude that intravenous lidocaine (1.5 mg X kg-1) significantly attenuates the IOP response to laryngoscopy and intubation in children anaesthetized with pancuronium, thiopentone, and atropine.
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This study determined which variables affected endotracheal tube "leak" pressures in 80 surgical patients, two weeks to 11 years of age, intubated with uncuffed tracheal tubes. We defined "leak" pressure as the inspiratory pressure needed to cause an audible escape of gas around the endotracheal tube. "Leak" pressure was measured after varying either head position, tracheal tube depth within the trachea, fresh gas flow rate, or degree of neuromuscular block. "Leak" pressure increased progressively from 16.9 +/- 1.3 cmH2O with complete patient paralysis to 30.6 +/- 1.4 cmH2O following 100 per cent recovery of neuromuscular function. ⋯ Thus, there may be marked variability in "leak" pressure, depending on head position and degree of neuromuscular blockade. Keeping the patient fully paralyzed with the head in a neutral position provides a reliable and consistent method for measuring "leak" pressures.
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A young healthy male, who had three consecutive episodes of postoperative hyperthermia was anaesthetized with special precautions to prevent malignant hyperthermia. Despite neuroleptic anaesthesia and dantrolene pretreatment, the patient experienced post-anaesthetic hyperthermia. ⋯ The serum potassium (K) and creatinine phosphokinase (CPK) levels determined during the hyperthermic episode and on the next day were not elevated. On the basis of the patient's family history, his clinical picture, and his laboratory data, we speculate that this patient might have a form of malignant hyperthermia or a possible new variant.
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Eighteen mongrel dogs were randomized into two equal groups. Cervical, thoracic and lumbosacral spinal cord and spinal dural blood flows were measured using the radioactive microsphere technique. Blood flow determinations were made prior to, and 20 and 40 minutes following lumbar subarachnoid injection of: (1) 0.4 per cent bupivacaine (20 mg), or (2) 0.4 per cent bupivacaine (20 mg) with 1/25,000 epinephrine (200 micrograms). ⋯ Dogs receiving subarachnoid bupivacaine with epinephrine demonstrated a significant decrease in thoracic and lumbosacral spinal cord blood flow; however, cervical cord blood flow remained unchanged. Thoracic and lumbosacral dural blood flows were significantly decreased in both groups following subarachnoid injection. Subarachnoid bupivacaine 0.4 per cent (20 mg) and 0.4 per cent with epinephrine 1/25,000 (200 micrograms) decrease spinal cord and spinal dural blood flow in dogs.